The present invention relates to a novel and useful detergent composition for domestic and industrial uses.
Usually, when a surface active agent is used as a main component of detergent, builder is added thereto. Although builder itself has no detergency, it excellently accelerates the detergency of surface active agent due to the chelating effect, dispersing power and other properties of builder.
Heretobefore, there have been known various kinds of compounds as builders. Among them, sodium salts or potassium salts of phosphoric acids such as tripolyphosphoric acid, tetrametaphosphoric acid and pyrophosphoric acid have been widely utilized in view of their excellent efficiency. However, these phosphates have various problems in other points than efficiency.
When waste washing water containing such a builder run into river, lake or sea, phosphorous components result in increasing nutriments of water weeds in water and accelerate the propagation of water weeds. Development of novel builders in place of phosphate type builders has been strongly required in view of environmental conservation. Recently, some kinds of builders other than phosphate type builders have been proposed, however, almost all of them have not yet been commercially utilized in view of efficiency as builder, safety and economical points.
Some of the inventors of the present invention have found and proposed that tri-alkali metal salts and tri-ammonium salt of imidobissulfuric acid are effective as builder in place of phosphates.
These tri-alkali metal salts and tri-ammonium salt of imidobissulfuric acid can be more economically supplied into market in comparison with sodium tripolyphosphate, which is the most conventional builder, and have good efficiency. However, these imidobissulfates are still not enough in chelating property and also in detergency.
As compared with sodium tripolyphosphate, they have to be added in a larger amount in order to show the same detergency as sodium tripolyphosphate. Even when using a larger amount of these imidobissulfates, waste water containing them does not accelerate the propagation of water weeds, but it is not preferable from the economical and other points of view to use a large amount thereof.
The inventors of the present invention have found that when some specific compound is used together with the imidobissulfate, the amount of the imidobissulfate to be added in place of phosphates into detergent composition is remarkably reduced and the detergency is remarkably increased. In other words, the inventors of the present invention attempted to use various conventional chelating agents in combination with the imidobissulfate and found that typical chelating agents such as tetrasodium ethylenediamine-tetraacetate, which has very high chelating property, do not show any substantial effect, but sodium nitrilotriacetate and/or sodium citrate in combination with the imidobissulfate show sharply improved detergency.